Analysis of viable and nonviable cells

ABSTRACT

Provided are methods, compositions, and kits for selectively analyzing a sample for viable cells and nonviable cells. For example, the method may include dyeing viable cells and/or nonviable with a membrane-permeable fluorescent dye, and dyeing nonviable cells with a membrane-impermeable fluorescent quenching dye. The method may include illuminating to cause fluorescent emission from the membrane-permeable fluorescent dye in the viable cells and the membrane-impermeable fluorescent quenching dye in the non-viable cells. The method may include quenching at least a portion of fluorescence of the membrane-permeable fluorescent dye in the nonviable cells by the membrane-impermeable fluorescent quenching dye. The method may include selectively analyzing the sample for the viable and nonviable cells.

BACKGROUND

There is current interest in techniques for identifying the presence ofcells, e.g., in a sample, such as a cancer biopsy, microbes in bodyfluids, medical products, foods, and the like. In many situations, itmay be desirable to analyze viable (e.g., live) cells and nonviable(e.g., dead) cells. It may also be desirable to distinguish betweenviable and non-viable cells. Further, it may be desirable to countand/or distinguish such cells simply and quickly.

Traditional cell culture methods for assessing viable and nonviablecells can take hours to days to perform, which can depend upon theorganisms that are being tested. Further, in order to separately analyzeviable and non-viable cells, complex instrumentation and time-consumingdata manipulation may be employed. For example, a variety of systemshave been developed that label viable cells with one fluorescent dye andlabel non-viable cells with both the first dye and a second, differentfluorescent dye. To separately analyze the viable and non-viable cells,illumination and detection may use multiple scans using specializedlight sources and/or filters to provide and receive selected bands oflight. Additionally, the fluorescence received from each dye may bemanipulated in software to separately view the viable cells from thenon-viable cells.

Viability dyes are known that may be activated within viable cells, forexample, by metabolic activity (e.g., esterase cleavage of esterfunctionalized pro-fluorophores) within the cells. The fluorescentbackground may be reduced by using a membrane-impermeable quencher, butin such an approach, only the viable cells are detected. Somefluorescent dyes are membrane-impermeable and preferentially labelnon-viable cells over viable cells. Some systems employ a combination ofone or more membrane-permeable dyes, one or more quenchers, and one ormore membrane-impermeable dyes. However, increasing amounts of thevarious dyes and quenchers may undesirably perturb the behavior ofviable cells or even kill them, and may also increase the generation ofhazardous waste.

The present application appreciates that conducting fluorescentcell-based assays may be a challenging endeavor.

SUMMARY OF THE INVENTION

In various embodiments, a method is provided for selectively analyzing asample for viable cells and nonviable cells. The method may includeproviding a sample that includes one or more viable cells and/or one ormore nonviable cells. The method may include contacting the sample witha membrane-permeable fluorescent dye and a membrane-impermeablefluorescent quenching dye. The fluorescent cell-dyeing conditions may beeffective to cause the one or more viable cells and/or the one or morenonviable cells to be dyed by the membrane-permeable fluorescent dye.The fluorescent cell-dyeing conditions may be effective to cause the oneor more nonviable cells to be dyed with the membrane-impermeablefluorescent quenching dye. The membrane-permeable fluorescent dye may becharacterized by a first fluorescent excitation band and a firstfluorescence emission band. The membrane-impermeable fluorescentquenching dye may be characterized by a second fluorescent excitationband and a second fluorescence emission band. The method may includeilluminating the sample under conditions effective to cause emitting ofthe first fluorescence emission band from the one or more viable cellsdyed by the membrane-permeable fluorescent dye. The method may includeilluminating the sample under conditions effective to cause emitting ofthe second fluorescence emission band from the one or more nonviablecells dyed by the membrane-impermeable fluorescent quenching dye. Themethod may include illuminating the sample under conditions effective tocause quenching of at least a portion of fluorescence of themembrane-permeable fluorescent dye in the one or more nonviable cells bythe membrane-impermeable fluorescent quenching dye. The method mayinclude selectively analyzing the sample for: a presence of the one ormore viable cells according to the first fluorescence emission bandand/or a presence of the one or more nonviable cells according to thesecond fluorescence emission band.

In various embodiments, a composition is provided. The composition mayinclude a membrane-permeable fluorescent dye. The membrane-permeable dyemay be characterized by a first fluorescent excitation band and a firstfluorescence emission band. The composition may include amembrane-impermeable fluorescent quenching dye. The membrane-impermeablefluorescent quenching dye may be characterized by a second fluorescentexcitation band and a second fluorescence emission band.

In various embodiments, a kit for selectively analyzing a sample forviable cells and nonviable cells is provided. The kit may include acomposition. The composition may include a membrane-permeablefluorescent dye. The membrane-permeable dye may be characterized by afirst fluorescent excitation band and a first fluorescence emissionband. The composition may include a membrane-impermeable fluorescentquenching dye. The membrane-impermeable fluorescent quenching dye may becharacterized by a second fluorescent excitation band and a secondfluorescence emission band. The kit may include instructions. Theinstructions may direct a user to provide a sample comprising one ormore viable cells and/or one or more nonviable cells. The instructionsmay direct a user to contact the sample with the composition. The one ormore viable cells and/or the one or more nonviable cells may be dyed bythe membrane-permeable fluorescent dye. The one or more nonviable cellsmay be dyed with the membrane-impermeable fluorescent quenching dye. Theinstructions may direct a user to illuminate the sample under conditionseffective to cause emitting of the first fluorescence emission band fromthe one or more viable cells dyed by the membrane-permeable fluorescentdye. The instructions may direct a user to illuminate the sample underconditions effective to cause emitting of the second fluorescenceemission band from the one or more nonviable cells dyed by themembrane-impermeable fluorescent quenching dye. The instructions maydirect a user to illuminate the sample under conditions effective tocause quenching of at least a portion of fluorescence of themembrane-permeable fluorescent dye in the one or more nonviable cells bythe membrane-impermeable fluorescent quenching dye. The instructions maydirect the user to selectively analyze the sample for: a presence of theone or more viable cells according to the first fluorescence emissionband and/or a presence of the one or more nonviable cells according tothe second fluorescence emission band.

Various features, aspects, and advantages of the present invention willbecome more apparent from the following detailed description ofpreferred embodiments of the invention, along with the accompanyingdrawings in which like numerals represent like components.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A is a confocal fluorescent microscopy image of a sample preparedby incubation with a membrane-impermeable fluorescent quenching dye for30 min followed by addition of the masking agent and incubation for anadditional 1 h.

FIG. 1B is a confocal fluorescent microscopy image of a sample preparedby incubation with the membrane-impermeable fluorescent quenching dyefor 30 min.

FIG. 1C is a confocal fluorescent microscopy image of a sample preparedby incubation with the membrane-impermeable fluorescent quenching dyefor 30 min, followed by addition of a membrane-permeable fluorescent dyeand incubation for an additional 1 h.

FIG. 1D is a confocal fluorescent microscopy image of a sample incubatedwith the membrane-impermeable fluorescent quenching dye for 30 min,followed by addition of the membrane-permeable fluorescent dye andmasking reagent and incubation for an additional 1 h.

FIG. 1E is a confocal fluorescent microscopy image of a sample preparedby incubation with the membrane-permeable fluorescent dye alone for 1 h.

FIG. 1F is a confocal fluorescent microscopy image of a sample preparedby incubation with the membrane-permeable fluorescent dye alone for 1 h,followed by addition of the membrane-impermeable fluorescent quenchingdye and incubation for an additional 30 min.

FIG. 1G is a confocal fluorescent microscopy image of a sample preparedby incubation with the membrane-permeable fluorescent dye and maskingreagent for 1 h, followed by addition of the membrane-impermeablefluorescent quenching dye and incubation for an additional 30 min.

FIGS. 2A & 2B are confocal fluorescent microscopy images of a sampleprepared by incubation with the membrane-permeable fluorescent dye,taken immediately after addition of the membrane-impermeable fluorescentquenching dye. FIG. 2B is an enlargement of the indicated section ofFIG. 2A.

FIGS. 2C & 2D are confocal fluorescent microscopy images of a sampleprepared by incubation with the membrane-permeable fluorescent dye,taken 5 min after addition of the membrane-impermeable fluorescentquenching dye. FIG. 2D is an enlargement of the indicated section ofFIG. 2C.

FIGS. 2E & 2F are confocal fluorescent microscopy images of a sampleprepared by incubation with the membrane-permeable fluorescent dye,taken 20 min after addition of the membrane-impermeable fluorescentquenching dye. FIG. 2F is an enlargement of the indicated section ofFIG. 2E.

FIGS. 2G & 2H are confocal fluorescent microscopy images of a sampleprepared by incubation with the membrane-permeable fluorescent dye,taken 30 min after addition of the membrane-impermeable fluorescentquenching dye. FIG. 2H is an enlargement of the indicated section ofFIG. 2G.

FIGS. 2I & 2J are confocal fluorescent microscopy images of a sampleprepared by incubation with the membrane-permeable fluorescent dye,taken 45 min after addition of the membrane-impermeable fluorescentquenching dye. FIG. 2J is an enlargement of the indicated section ofFIG. 2I.

DETAILED DESCRIPTION

This document relates generally to a method, composition and kit capableof selectively analyzing, e.g., detecting and distinguishing a presenceof viable and/or nonviable cells in a cell sample. The method,composition, and kit may distinguish viable and non-viable cells usingonly two dyes, a membrane-permeable fluorescent dye and amembrane-impermeable fluorescent quencher. The method, composition, andkit may distinguish viable and non-viable cells using broad-bandillumination, without the need for lasers or other specialized, filteredlight sources. The method, composition, and kit may distinguish viableand non-viable cells using a single image, e.g., a fluorescencemicroscope image, without requiring separate scans or deconvolution insoftware. The method, composition, and kit may distinguish viable andnon-viable cells using dyeing methods that are effective within lessthan two hours. In particular, this document describes a method,composition and kit for detecting viable cells in a cell sample using amembrane-permeable fluorescent dye that permeates both viable andnon-viable cells, and a membrane-impermeable fluorescent quenching dyethat selectively permeates non-viable cells. Under suitableillumination, the membrane-permeable fluorescent label may exhibitfluorescence in the viable cells. In the nonviable cells, under thesuitable illumination, the membrane-impermeable fluorescent quenchingdye may quench at least a portion of fluorescence by themembrane-permeable fluorescent dye and the membrane-impermeablefluorescent quenching dye may itself exhibit fluorescence. Accordingly,the viable and non-viable cells may both be detected, and may bedistinguished according to fluorescence in the viable cells of themembrane-permeable fluorescent dye and fluorescence in the nonviablecells by the membrane-impermeable fluorescent quenching dye.

In various embodiments, a method is provided for selectively analyzing asample for viable cells and nonviable cells. The method may includeproviding a sample that includes or is suspected to include one or moreviable cells and/or one or more nonviable cells. The method may includecontacting the sample with a membrane-permeable fluorescent dye and amembrane-impermeable fluorescent quenching dye under fluorescentcell-dyeing conditions. The fluorescent cell-dyeing conditions may beeffective to cause the one or more viable cells and/or the one or morenonviable cells to be dyed by the membrane-permeable fluorescent dye.The fluorescent cell-dyeing conditions may be effective to cause the oneor more nonviable cells to be dyed with the membrane-impermeablefluorescent quenching dye.

The membrane-permeable fluorescent dye may be characterized by a firstfluorescent excitation band and a first fluorescence emission band. Themembrane-impermeable fluorescent quenching dye may be characterized by asecond fluorescent excitation band and a second fluorescence emissionband. The first fluorescent excitation band may be distinct from thesecond fluorescent excitation band. The first fluorescent emission bandmay be distinct from the second fluorescent emission band. The firstfluorescent emission band may overlap the second fluorescent excitationband.

The method may include illuminating the sample under conditionseffective to cause emitting of the first fluorescence emission band fromthe one or more viable cells dyed by the membrane-permeable fluorescentdye. The method may include illuminating the sample under conditionseffective to cause emitting of the second fluorescence emission bandfrom the one or more nonviable cells dyed by the membrane-impermeablefluorescent quenching dye. The method may include illuminating thesample under conditions effective to cause quenching of at least aportion of fluorescence of the membrane-permeable fluorescent dye in theone or more nonviable cells by the membrane-impermeable fluorescentquenching dye. The method may include selectively analyzing the samplefor: a presence of the one or more viable cells according to the firstfluorescence emission band and/or a presence of the one or morenonviable cells according to the second fluorescence emission band.

In some embodiments, the sample may include no viable cells. The samplemay include no nonviable cells. The sample may include no viable cellsand no nonviable cells. The sample may include at least one cell, viableor nonviable.

In some embodiments, the method may include selectively analyzing thesample. Selectively analyzing the sample may include detecting a numberof the one or more viable cells present in the sample. The number of theone or more viable cells present in the sample may be, for example, 1,5, 10, 15, 20, 25, 50, 75, 100, 150, 200, 250, 500, 750, 1,000, 1,250,1,500, 1,750, 2,000, 2,500, 5,000, 7,500, 10,000, or a range between anytwo of the preceding values, for example, between about 1-10,000,1-1,000, 1-500, 1-250, 1-100, and the like. Selectively analyzing thesample may include detecting a number of the one or more nonviable cellspresent in the sample. The number of the one or more nonviable cellspresent in the sample may be, for example, 1, 5, 10, 15, 20, 25, 50, 75,100, 150, 200, 250, 500, 750, 1,000, 1,250, 1,500, 1,750, 2,000, 2,500,5,000, 7,500, 10,000, or a range between any two of the precedingvalues, for example, between about 1-10,000, 1-1,000, 1-500, 1-250,1-100, and the like. Selectively analyzing the sample may includedetecting the presence of a plurality of the one or more viable cells.Selectively analyzing the sample may include detecting the presence of aplurality the one or more nonviable cells.

In several embodiments, illuminating the sample may include selectivelyilluminating in the first excitation band corresponding to themembrane-permeable fluorescent dye. Illuminating the sample may includeselectively illuminating in the second excitation band corresponding tothe membrane-impermeable fluorescent quenching dye. Selectivelyilluminating may include, for each excitation band, using acorresponding light source that is selective for each excitation band,each corresponding light source comprising one or more of: a laser, alight emitting diode, and a filtered broadband light source.Illuminating the sample may include contacting the sample withbroad-band illumination. The broad-band illumination may overlap thefirst excitation band corresponding to the membrane-permeablefluorescent dye. The broad-band illumination may overlap the secondexcitation band corresponding to the membrane-impermeable fluorescentquenching dye.

In some embodiments, selectively analyzing the sample for the one ormore viable cells and/or the one or more nonviable cells may includefiltering light emitted from the sample using a first emission filterthat is selective for the first fluorescence emission band. Selectivelyanalyzing the sample for the one or more viable cells and/or the one ormore nonviable cells may include filtering light emitted from the sampleusing a second emission filter that is selective for the secondfluorescence emission band.

Selectively analyzing the sample may include analyzing light emittedfrom the sample simultaneously for the first fluorescence emission bandand the second fluorescence emission band. The method may includedistinguishing the one or more viable cells and/or the one or morenonviable cells according to a spectral difference between the firstfluorescence emission band and the second fluorescence emission band.

Selectively analyzing the sample for the one or more viable cells and/orthe one or more nonviable cells may include acquiring an image of thesample using light emitted by the first fluorescence emission band andthe second fluorescence emission band. Selectively analyzing the samplefor the one or more viable cells and/or the one or more nonviable cellsmay include distinguishing the one or more viable cells and/or the oneor more nonviable cells in the image according to a first colorcorresponding to the first fluorescence emission band and a second colorcorresponding to the second fluorescence emission band.

Selectively analyzing the sample for the one or more viable cells and/orthe one or more nonviable cells may include acquiring an image of thesample using light emitted by the first fluorescence emission band andthe second fluorescence emission band. Selectively analyzing the samplefor the one or more viable cells and/or the one or more nonviable cellsmay include determining a number of the one or more viable cells in theimage according to light emitted by the first fluorescence emissionband, and a number of the one or more nonviable cells in the imageaccording to light emitted by the second fluorescence emission band.Selectively analyzing the sample for the one or more viable cells mayinclude determining a number of the one or more viable cells in theimage by counting cells and/or cell nuclei corresponding to the firstfluorescence emission band. Selectively analyzing the sample for the oneor more nonviable cells may include determining a number of the one ormore nonviable cells in the image by counting cells and/or cell nucleicorresponding to the second fluorescence emission band.

In various embodiments, the illumination may include a wavelength innanometers (nm) of one of about 350, 400, 450, 500, 550, 600, 650, 700,750, 800, 850, 900, 950, or 1000, or a range between about any two ofthe preceding values, for example, 350-1000 nm, 350-400 nm, 350-450 nm,350-500 nm, 350-550 nm, 350-600 nm, 400-450 nm, 400-500 nm, 400-550 nm,400-600 nm, 400-650 nm, 450-500 nm, 450-550 nm, 450-600 nm, 450-650 nm,450-700 nm, 500-550 nm, 500-600 nm, 500-650 nm, 500-700 nm, 500-750 nm,550-600 nm, 550-650 nm, 550-700 nm, 550-750 nm, 550-800 nm, 600-650 nm,600-700 nm, 600-750 nm, 600-800 nm, 600-850 nm, 650-700 nm, 650-750 nm,650-800 nm, 650-850 nm, 650-900 nm, 700-750 nm, 700-800 nm, 700-850 nm,700-900 nm, 700-950 nm, 750-800 nm, 750-850 nm, 750-900 nm, 750-950 nm,750-1000 nm, and the like.

In some embodiments, each fluorescent emission band can be detected at awavelength in nanometers (nm) of one of about 350, 400, 450, 500, 550,600, 650, 700, 750, 800, 850, 900, 950, or 1000, or a range betweenabout any two of the preceding values, for example, 350-1000 nm, 350-400nm, 350-450 nm, 350-500 nm, 350-550 nm, 350-600 nm, 400-450 nm, 400-500nm, 400-550 nm, 400-600 nm, 400-650 nm, 450-500 nm, 450-550 nm, 450-600nm, 450-650 nm, 450-700 nm, 500-550 nm, 500-600 nm, 500-650 nm, 500-700nm, 500-750 nm, 550-600 nm, 550-650 nm, 550-700 nm, 550-750 nm, 550-800nm, 600-650 nm, 600-700 nm, 600-750 nm, 600-800 nm, 600-850 nm, 650-700nm, 650-750 nm, 650-800 nm, 650-850 nm, 650-900 nm, 700-750 nm, 700-800nm, 700-850 nm, 700-900 nm, 700-950 nm, 750-800 nm, 750-850 nm, 750-900nm, 750-950 nm, 750-1000 nm, and the like.

Illuminating and selectively analyzing the sample may include using oneor more of any fluorescence analysis technique or fluorescenceanalytical device known to the art, for example, one or more of:fluorescence imaging, fluorescence spectroscopy, fluorescence imagingmicroscopy, epifluorescence microscopy, confocal fluorescence imagingmicroscopy, a fluorometer, a fluorescence microplate reader,fluorescence flow cytometry, and the like.

In various embodiments, the method may include providing the sample in acell culture device. The cell culture device may include, for example,at least one of: a multiwell plate, a multiwell strip, an optical cell,and a flow cytometry apparatus.

The cell culture device may include a chamber or conduit for liquid,such as a well, an optical cell, a culture dish, a microtiter plate, acuvette, a capillary tube, a flow cell, a flow cytometry apparatus, andthe like. The cell culture device may include a solid support, forexample, a microscope slide or a filter surface. The cell culture devicemay include a material selected to be substantially free ofautofluorescence when exposed to light having a wavelength in the rangefrom about 350 nm to about 1000 nm, or in a subrange corresponding tothe excitation bands of the membrane-permeable dye and themembrane-impermeable dye. Suitable substrates that are nonauto-fluorescent in at least some wavelength ranges of interest mayinclude, e.g., glass, quartz, sapphire, polystyrene, a nylon,nitrocellulose, polycarbonate, polyacrylic acid, poly(methylmethacrylate) (PMMA), polyester, polysulfone, polytetrafluoroethylene(PTFE), polyethylene, polypropylene, and the like.

The cell culture device may include at least one window. Illuminatingthe sample may be conducted through the at least one window. Selectivelyanalyzing the sample may be conducted through the at least one window.The cell culture device may include at least one optically flat window.Selectively analyzing the sample may include using any fluorescenceanalysis technique or fluorescence analytical device known to the art,for example, fluorescence imaging, fluorescence spectroscopy,fluorescence imaging microscopy, epifluorescence microscopy, confocalfluorescence imaging microscopy, a fluorometer, a fluorescencemicroplate reader, fluorescence flow cytometry, and the like. Forexample, selectively analyzing the sample may include, for example,conducting confocal fluorescence imaging microscopy of the samplethrough the at least one optically flat imaging window.

In several embodiments, the method may include culturing the one or moreviable cells in the sample under cell culture conditions. The cellculture conditions may include a temperature in ° C. of about one of:20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37,38, 39, or 40, or a range between any two of the preceding values, forexample, between about 20-40° C., 25-40° C., 30-40° C., 35-40° C., andthe like. The cell culture conditions may include a pH value of one ofabout: 6, 6.25, 6.5, 6.6, 6.7, 6.8, 6.9, 7, 7.1, 7.2, 7.3, 7.4, 7.5,7.6, 7.7, 7.8, 7.9, or 8, or a range between about any two of thepreceding values, for example, pH 6-8, pH 7-8, pH7-7.6, pH 7.3-7.5, andthe like. The cell culture conditions may include a presence of a cellculture medium. The cell culture medium may include, for example, water,salt, a buffer, nutrients, and the like. The cell culture medium mayinclude, for example, serum, e.g., fetal bovine serum, human serum,autologous serum from a subject from which the sample and cells arederived, and the like. For example, human primary tumor cells may becultured in serum derived from the human subject from whom the humanprimary tumor cells were derived.

Culturing the sample under cell culture conditions may permit growthand/or proliferation of the viable cells. The viable and non-viablecells may be further analyzed by standard procedures, for example,amplification procedures including polymerase chain reaction, ligasechain reaction, rolling circle replication, and the like, and nucleicacid sequencing.

Selectively analyzing the sample may be conducted at two or more pointsin time to determine, for example, a presence or absence of a change inthe one or more viable cells and/or the one or more nonviable cells. Forexample, selectively analyzing the sample may be conducted at two ormore points in time to determine a presence or an absence of a change ina number of the one or more viable cells and/or a number of the one ormore nonviable cells.

In some embodiments, the method may include contacting the sample withat least one agent. The method may include selectively analyzing thesample, including selectively analyzing the one or more viable cellsand/or the one or more nonviable cells for a presence or an absence of achange in response to the at least one agent. The method may includeselectively analyzing the presence or the absence of the response withrespect to an overall sample concentration of the at least one agent.The method may include selectively analyzing the presence or the absenceof the response with respect to a concentration gradient in the sample.The method may include selectively analyzing the presence or the absenceof the response with respect to a time variation of the overall sampleconcentration. The method may include selectively analyzing the presenceor the absence of the response with respect to a time variation of theconcentration gradient in the sample.

In various embodiments, the at least one agent may include, for example,a gas, a metabolite, a nutrient, a biomolecule, an acid, a base, abuffer, a salt, and a therapeutic drug. For example, the at least oneagent may include an anticancer agent, a therapeutic drug used as anadjunct in cancer therapy, a compound suspected of modulating cancertherapy, or the like. The at least one agent may include an adjuvanttherapy, for example, one or more of: supraphysiological temperature,radiation, subphysiological temperature, sonotherapy, and electrochemotherapy.

In some embodiments, the sample may include a three-dimensionalmicro-tissue formed of a plurality of cells, e.g., the one or moreviable cells and/or the one or more nonviable cells. The cells may be,for example, prokaryotic cells or eukaryotic cells. The method may beused to determine the number of viable cells and non-viable cells in atleast a portion of the sample, for example, a liquid sample. The liquidsample may be, for example, a water sample, an ingestible fluid, e.g.,wine, beer, milk, baby formula or the like, a body fluid, e.g., blood,lymph, urine, lung interstitial fluid, cerebrospinal fluid or the like),growth media, a liquid sample produced by harvesting cells from a sourceof interest, e.g., via a biopsy. The sample may include prokaryoticcells. The sample may include eukaryotic cells. The sample may includemammalian cells. The sample may include human cells. The sample mayinclude cancer cells, e.g., from a cancer cell line. The sample mayinclude cancer cells from a subject, e.g., primary tumor cells. Thesample may include cells of a patient-derived cancer cell xenograft. Thesample may include primary tumor cells from a single human subject. Thesample may include cells grown in a xenograft of primary cells derivedfrom a single human subject.

In several embodiments, the method may include contacting the samplewith the membrane-permeable fluorescent dye before themembrane-impermeable fluorescent quenching dye. The method may includecontacting the sample with the membrane-permeable fluorescent dye afterthe membrane-impermeable fluorescent quenching dye. The method mayinclude contacting the sample with the membrane-permeable fluorescentdye at the same time as the membrane-impermeable fluorescent quenchingdye. The method may include contacting the sample with a compositioncomprising the membrane-permeable fluorescent dye together with themembrane-impermeable fluorescent quenching dye.

In various embodiments, the membrane-permeable fluorescent dye and themembrane-impermeable fluorescent quenching dye may be cell-structureselective dyes. For example, the membrane-permeable fluorescent dye andthe membrane-impermeable fluorescent quenching dye may be nucleic acidbinding dyes. In certain embodiments, the membrane-permeable fluorescentdye and the membrane-impermeable fluorescent quenching dye may bind toone another, e.g., in the non-viable cells.

The method may include contacting the sample with an amount of themembrane-impermeable fluorescent quenching dye, e.g. compared to anamount of the membrane-permeable fluorescent dye, effective to providethe quenching of at least a portion of fluorescence of themembrane-permeable fluorescent dye in the one or more nonviable cells.The amount of the membrane-impermeable fluorescent quenching dye may beeffective to substantially quench fluorescence of the membrane-permeablefluorescent dye in the one or more nonviable cells. The amount of themembrane-impermeable fluorescent quenching dye may be effective toquench fluorescence of the membrane-permeable fluorescent dye in the oneor more nonviable cells by a percentage of the unquenched fluorescenceof at least about one of: 50, 75, 80, 85, 90, 95, 96, 97, 98, 99, 99.5,99.6, 99.7, 99.8, 99.9, 99.95, 99.99, 99.995, 99.999, 99.9995, 99.9999,100, and the like, or a range between any two of the preceding values,for example, between about 95% and 100%, 99%, and 100%, and the like.

In some embodiments, the first fluorescent emission band may becharacterized by an overlap with an excitation band of themembrane-impermeable fluorescent quenching dye. The overlap may beeffective to provide the quenching of at least a portion of fluorescenceof the membrane-permeable fluorescent dye in the one or more nonviablecells by the membrane-impermeable fluorescent quenching dye. The overlapmay be effective to provide resonant energy transfer from an excitedstate of the membrane-permeable fluorescent dye to a ground state of themembrane-impermeable fluorescent quenching dye. Without wishing to bebound by theory, the resonant energy transfer may be radiationless,e.g., as known to the art under the term Föerster resonant energytransfer.

In various embodiments, the membrane-permeable fluorescent dye may beselected from Table 1. The membrane-impermeable fluorescent quenchingdye may be selected from Table 2. A pair of dyes may be used including amembrane-permeable fluorescent dye selected from Table I and amembrane-impermeable fluorescent quenching dye selected from Table II(all dyes available from Thermo Fisher Scientific, Waltham, Mass.). Apair of dyes may be used including any pair of dyes (a), (b), (c), (d),or (x) as indicated in Table III. A pair of dyes may be used includingany pair of dyes (a), (b), (c), or (d) as indicated in Table III. A pairof dyes may be used including any pair of dyes (a), (b), or (c) asindicated in Table III. A pair of dyes may be used including any pair ofdyes (a) or (b) as indicated in Table III. A pair of dyes may be usedincluding any pair of dyes (a) indicated in Table III. A pair of dyesmay be used including any pair of dyes (b) indicated in Table III. Apair of dyes may be used including any pair of dyes (c) indicated inTable III. A pair of dyes may be used including any pair of dyes (d)indicated in Table III. A pair of dyes may be used including any pair ofdyes (x) indicated in Table III.

In various embodiments, a composition is provided. The composition mayinclude a membrane-permeable fluorescent dye. The membrane-permeable dyemay be characterized by a first fluorescent excitation band and a firstfluorescence emission band. The composition may include amembrane-impermeable fluorescent quenching dye. The membrane-impermeablefluorescent quenching dye may be characterized by a second fluorescentexcitation band and a second fluorescence emission band.

In some embodiments, the membrane-permeable fluorescent dye and themembrane-impermeable fluorescent quenching dye may be cell-structureselective dyes. For example, the membrane-permeable fluorescent dye andthe membrane-impermeable fluorescent quenching dye may be nucleic acidbinding dyes.

TABLE 1 Membrane Permeable Fluorescent Dyes # Dye excitation λ_(max)emission λ_(max) p1 Acridine Orange 502 525 p2 Hoechst 33258 355 465 P3Hoechst 33342 355 465 p4 VYBRANT ™ DYECYCLE ™ 369 437 Violet P5VYBRANT ™ DYECYCLE ™ 506 534 Green p6 VYBRANT ™ DYECYCLE ™ 519 563Orange p7 VYBRANT ™ DYECYCLE ™ 638 686 Ruby p8 DRAQ5 ™ 488, 647 697 p9CyQUANT ® GR 501 521 p10 SYTO ™ 40 422 447 p11 SYTO ™ 41 425 452 p12SYTO ™ 42 436 470 p13 SYTO ™ 43 443 465 p14 SYTO ™ 44 449 475 p15 SYTO ™45 451 484 p16 SYTO ™ 9 485 498 p17 SYTO ™ 11 508 527 p18 SYTO ™ 13 488509 p19 SYTO ™ 14 517 549 p20 SYTO ™ 16 488 518 p21 SYTO ™ 80 531 545p22 SYTO ™ 81 530 544 p23 SYTO ™ 82 541 560 p24 SYTO ™ 83 543 559 p25SYTO ™ 84 567 582 p26 SYTO ™ 85 567 583 p27 SYTO ™ 17 621 634 p28 SYTO ™59 622 645 p29 SYTO ™ 60 652 678 p30 SYTO ™ 61 628 645 p31 SYTO ™ 62 652676

TABLE 2 Membrane Impermeable Fluorescent Quenching Dyes excitationemission # Name CAS λ_(max) λ_(max) q1 4′,6-diamidino-2- 28718-90-3 358461 phenylindole (DAPI) q2 Ethidium bromide 1239-45-8 300, 360 590 q3Propidium Iodide 25535-16-4 493 636 q4 7AAD (7-amino 7240-37-1 546 647actinomycin D) q5 SYTOX ™ blue 396077-00-2 444 480 q6 SYTOX ™ green194100-76-0 504 523 q7 SYTOX ™ orange 324767-53-5 547 570 q8 SYTOX ™ red— 640 658 q9 POPO ™-1 169454-15-3 434 456 q10 BOBO ™-1 169454-13-1 462481 q11 YOYO ™-1 143413-85-8 491 509 q12 TOTO ™-1 143413-84-7 514 533q13 JOJO ™-1 305801-87-0 529 545 q14 POPO ™-3 154757-99-0 534 570 q15BOBO ™-3 169454-17-5 570 602 q16 YOYO ™-3 156312-20-8 612 631 q17TOTO ™-3 166196-17-4 642 660 q18 DRAQ7 ™ 1533453-55-2 599, 644 678

TABLE 3 Pairs of Membrane Permeable Fluorescent Dye/ MembraneImpermeable Fluorescent Quenching Dye q1 q2 q3 q4 q5 q6 q7 q8 q9 q10 q11q12 q13 q14 q15 q16 q17 q18 p1 x a a a x x b c x x x d a a b c d b p2 xb c b d b c d x b b c c b c c d d p3 x b c b d b c d x x x d c b c c d dp4 x b c c b c c d b b c d c b d d d d p5 x a c a d x a c x x x x a a bc c b p6 x b d b x x x c x x x x x c a c c a p7 x x x x x x x x x x x xx x x x x x p8 x x x x x x x x x x x x x x x x x x p9 x a c a x x b d xx x d b a b c d b p10 x c c c b c d d d b b c c b c d d x p11 x c c c cc d d x a b c c c d d d x p12 x b c b x b c d x b b c c c c d d d p13 xb c b x b c d x c c c c c c d d d p14 x b c b x b c d x d c b c c c d dd p15 x b c b x b c c x x c b c b c c d d p16 x a b a x a c d x x x b cb c c d d p17 x a b a x x b c x x x x a a b b c c p18 x a b a x b b c xx x a b b c c d d p19 x a b a x x b c x x x d a a b b c c p20 x a b a xd b c x x x b a a b c c c p21 x x x c x x x b x x x x x x x b b a p22 xc c b x x x b x x x x x b a b c c p23 x c c a x x x c x x x x x c a c db p24 x d d b x x x c x x x x x x a c d b p25 x x x x x x x x x x x x xx x x x b p26 x d d c x x x c x x x x x x c b b a p27 x x x x x x x a xx x x x x x x a b p28 x x x x x x x a x x x x x x x x a b p29 x x x x xx x x x x x x x x x x x x p30 x x x x x x x c x x x x x x x x d b p31 xx x x x x x x x x x x x x x x x x

In several embodiments, the composition may be characterized by themembrane-impermeable fluorescent quenching dye and themembrane-permeable fluorescent dye in respective amounts effective toprovide quenching of fluorescence of the membrane-permeable fluorescentdye by the membrane-impermeable fluorescent quenching dye underillumination conditions effective to cause one or more of: excitation ofthe first fluorescent excitation band, emission of the firstfluorescence emission band, excitation of the second fluorescentexcitation band, and emission of the first fluorescence emission band.The membrane-impermeable fluorescent quenching dye and themembrane-permeable fluorescent dye may be in respective amountseffective to provide substantial quenching of fluorescence of themembrane-permeable fluorescent dye by the membrane-impermeablefluorescent quenching dye under illumination conditions effective tocause one or more of: excitation of the first fluorescent excitationband, emission of the first fluorescence emission band, excitation ofthe second fluorescent excitation band, and emission of the firstfluorescence emission band. The amount of the membrane-impermeablefluorescent quenching dye may be effective to quench fluorescence of themembrane-permeable fluorescent dye under the illumination conditions,e.g., in the one or more nonviable cells, by a percentage of theunquenched fluorescence of at least about one of: 50, 75, 80, 85, 90,95, 96, 97, 98, 99, 99.5, 99.6, 99.7, 99.8, 99.9, 99.95, 99.99, 99.995,99.999, 99.9995, 99.9999, 100, and the like, or a range between any twoof the preceding values, for example, between about 95% and 100%, 99%,and 100%, and the like.

Without wishing to be bound by theory, the membrane-impermeablefluorescent quenching dyes described may quench fluorescence from themembrane-permeable fluorescent dye by either photo-induced electrontransfer (PET), sometimes referred to as static quenching, or Föersterresonance energy transfer (FRET), or some combination thereof. Thequenching efficiency may be distance-dependent. Conditions may beselected to facilitate quenching.

For example, the membrane-permeable fluorescent dye and themembrane-impermeable fluorescent quenching dye may be selected such thatthe first fluorescent emission band overlaps with the second excitationband effective to provide quenching of at least a portion offluorescence of the membrane-permeable fluorescent dye by themembrane-impermeable fluorescent quenching dye, e.g., under fluorescentcell-dyeing conditions. The overlap may be effective to provide resonantenergy transfer from an excited state of the membrane-permeablefluorescent dye to a ground state of the membrane-impermeablefluorescent quenching dye. Without wishing to be bound by theory, theresonant energy transfer may be radiationless, e.g., as known to the artunder the term Föerster resonant energy transfer.

For example, the fluorescent membrane-permeable fluorescentdye/membrane-impermeable fluorescent quenching dye pairs may be selectedto have a binding affinity for one another, for example, viaelectrostatic and/or hydrophobic interactions, which may bind to form asubstantially quenched non-fluorescent ground-state complex, e.g., inthe non-viable cells. The membrane-impermeable quencher may be excludedby the membrane of the viable cells so the non-fluorescent complex maybe excluded from viable cells.

Further, for example, the fluorescent membrane-permeable fluorescent dyeand/or membrane-impermeable fluorescent quenching dye may be selectedfor binding affinities for a cellular component, organelle, orstructure, such as nucleic acids. When the fluorescentmembrane-permeable fluorescent dye and membrane-impermeable fluorescentquenching dye are co-bound to a specific target, such as a nucleic acidin a non-viable cell, the proximity of the dye and quencher mayfacilitate formation of a substantially quenched, non-fluorescentcomplex. The membrane-impermeable quencher may be excluded by themembrane of the viable cells so the non-fluorescent complex may beexcluded from viable cells.

In various embodiments, the membrane-permeable fluorescent dye may beselected from Table 1. The membrane-impermeable fluorescent quenchingdye may be selected from Table 2. A pair of dyes may be used including amembrane-permeable fluorescent dye selected from Table I and amembrane-impermeable fluorescent quenching dye selected from Table II. Apair of dyes may be used including any pair of dyes (a), (b), (c), (d),or (x) as indicated in Table III. A pair of dyes may be used includingany pair of dyes (a), (b), (c), or (d) as indicated in Table III. A pairof dyes may be used including any pair of dyes (a), (b), or (c) asindicated in Table III. A pair of dyes may be used including any pair ofdyes (a) or (b) as indicated in Table III. A pair of dyes may be usedincluding any pair of dyes (a) indicated in Table III. A pair of dyesmay be used including any pair of dyes (b) indicated in Table III. Apair of dyes may be used including any pair of dyes (c) indicated inTable III. A pair of dyes may be used including any pair of dyes (d)indicated in Table III. A pair of dyes may be used including any pair ofdyes (x) indicated in Table III.

In various embodiments, the composition may include a physiologicallyacceptable buffer selected to maintain a pH value. The cell cultureconditions may include a pH value of one of about: 6, 6.25, 6.5, 6.6,6.7, 6.8, 6.9, 7, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, or 8, ora range between about any two of the preceding values, for example, pH6-8, pH 7-8, pH7-7.6, pH 7.3-7.5, and the like. The composition mayinclude a cell culture medium. The cell culture medium may include, forexample, water, salt, a buffer, nutrients, and the like. The cellculture medium may include, for example, serum, e.g., fetal bovineserum, human serum, autologous serum from a subject from which thesample and cells are derived, and the like. For example, human primarytumor cells may be cultured in serum derived from the human subject fromwhom the human primary tumor cells were derived. The composition mayinclude one or more of: a gas, a metabolite, a nutrient, a biomolecule,an acid, a base, a buffer, a salt, and a therapeutic drug. Thecomposition may include one or more of: an anticancer agent, atherapeutic drug used as an adjunct in cancer therapy, a compoundsuspected of modulating cancer therapy, or the like.

In various embodiments, a kit for selectively analyzing a sample forviable cells and nonviable cells is provided. The kit may include acomposition. The composition may include a membrane-permeablefluorescent dye. The membrane-permeable dye may be characterized by afirst fluorescent excitation band and a first fluorescence emissionband. The composition may include a membrane-impermeable fluorescentquenching dye. The membrane-impermeable fluorescent quenching dye may becharacterized by a second fluorescent excitation band and a secondfluorescence emission band. The kit may include instructions. Theinstructions may direct a user to provide a sample comprising one ormore viable cells and/or one or more nonviable cells. The instructionsmay direct a user to contact the sample with the composition. The one ormore viable cells and/or the one or more nonviable cells may be dyed bythe membrane-permeable fluorescent dye. The one or more nonviable cellsmay be dyed with the membrane-impermeable fluorescent quenching dye. Theinstructions may direct a user to illuminate the sample under conditionseffective to cause emitting of the first fluorescence emission band fromthe one or more viable cells dyed by the membrane-permeable fluorescentdye. The instructions may direct a user to illuminate the sample underconditions effective to cause emitting of the second fluorescenceemission band from the one or more nonviable cells dyed by themembrane-impermeable fluorescent quenching dye. The instructions maydirect a user to illuminate the sample under conditions effective tocause quenching of at least a portion of fluorescence of themembrane-permeable fluorescent dye in the one or more nonviable cells bythe membrane-impermeable fluorescent quenching dye. The instructions maydirect the user to selectively analyze the sample for: a presence of theone or more viable cells according to the first fluorescence emissionband and/or a presence of the one or more nonviable cells according tothe second fluorescence emission band.

In various embodiments, the kit may include instructions to direct theuser to conduct any aspect of the method described herein. The kit mayinclude any aspect of the composition described herein.

EXAMPLES

The invention may be readily understood by reference to the followingexamples, which are included merely for purposes of illustration ofcertain aspects and embodiments of the present invention, and are notintended to limit the scope of the invention in any way.

Example 1

A 96 round bottom well plate was seeded with a single cell suspension ofabout 2,500 ovarian cancer primary tumor cells/20 μl/well at day 0. Ineach well, 80 μl of DMEM/2% alpha serum was added on top to the totalvolume of 100 μl/well. Dyes were prepared at 2-fold the desired finalconcentrations on the day of imaging. At day 3, 100 μL of dyeing mix wascarefully added to each well to avoid disturbing the cells, to a final1-fold concentration of dyes. Cells were incubated with dyes at 37° C.For this example, the dyes used were a membrane-permeable fluorescentdye (CYQUANT® GR, Thermo Fisher Scientific, Waltham, Mass.) and amembrane-impermeable fluorescent quenching dye (DRAQ7™, Thermo FisherScientific, Waltham, Mass.). The following dye combinations andsequences of dye addition were tested in triplicates, and similarresults were seen among the triplicates. FIGS. 1A-1G show exemplaryresults of the dye combination and addition sequences, as follows.

FIG. 1A is a confocal fluorescent microscopy image of a sample preparedby incubation with the membrane-impermeable fluorescent quenching dyefor 30 min followed by addition of the masking agent (Diammonium5-[(E)-(4-acetamido-2-sulfonatophenyl)diazenyl]-6-amino-4-hydroxy-2-naphthalenesulfonate;CAS Reg. No. 302912-22-7, Thermo Fischer Scientific, Waltham, Mass.) andincubation for an additional 1 h. Under conventional confocalfluorescent microscopy conditions used for imaging cells, no signal wasobserved.

FIG. 1B is a confocal fluorescent microscopy image of a sample preparedby incubation with the membrane-impermeable fluorescent quenching dyefor 30 min. Under conventional confocal fluorescent microscopyconditions used for imaging cells, discrete red signals were observed,consistent with dyeing of nonviable cells.

FIG. 1C is a confocal fluorescent microscopy image of a sample preparedby incubation with the membrane-impermeable fluorescent quenching dyefor 30 min, followed by addition of the membrane-permeable fluorescentdye and incubation for an additional 1 h. Under conventional confocalfluorescent microscopy conditions used for imaging cells, discrete redsignals were observed, consistent with dyeing of nonviable cells, aswere discrete green signals, consistent with dyeing of viable cells.

FIG. 1D is a confocal fluorescent microscopy image of a sample preparedby incubation with the membrane-impermeable fluorescent quenching dyefor 30 min, followed by addition of the membrane-permeable fluorescentdye and masking reagent and incubation for an additional 1 h. Underconventional confocal fluorescent microscopy conditions used for imagingcells, discrete green signals were observed, consistent with dyeing ofviable cells. No red signal was observed, consistent with permeation ofthe nonviable cells with the masking agent and blocking/quenching of themembrane-impermeable fluorescent quenching dye and themembrane-permeable fluorescent dye signal from the non-viable cells.

FIG. 1E is a confocal fluorescent microscopy image of a sample preparedby incubation with the membrane-permeable fluorescent dye alone for 1 h.Under conventional confocal fluorescent microscopy conditions used forimaging cells, discrete green signals were observed, consistent withdyeing of viable cells. FIG. 1E is comparable to FIG. 1D, where amasking agent was added to block fluorescence from nonviable cells.

FIG. 1F is a confocal fluorescent microscopy image of a sample preparedby incubation with the membrane-permeable fluorescent dye alone for 1 h,followed by addition of the membrane-impermeable fluorescent quenchingdye and incubation for an additional 30 min. Under conventional confocalfluorescent microscopy conditions used for imaging cells, discrete redsignals were observed, consistent with dyeing of nonviable cells, aswere discrete green signals, consistent with dyeing of viable cells.FIG. 1F is comparable to FIG. 1C.

FIG. 1G is a confocal fluorescent microscopy image of a sample preparedby incubation with the membrane-permeable fluorescent dye and maskingreagent for 1 h, followed by addition of the membrane-impermeablefluorescent quenching dye and incubation for an additional 30 min. Underconventional confocal fluorescent microscopy conditions used for imagingcells, discrete green signals were observed, consistent with dyeing ofviable cells. No red signal was observed, consistent with permeation ofthe nonviable cells with the masking agent and blocking/quenching of themembrane-impermeable fluorescent quenching dye signal. FIG. 1D iscomparable to FIGS. 1D and 1E.

Discussion

The membrane-permeable fluorescent dye alone dyed both viable andnonviable cells. The addition of masking agent also appeared to blockfluorescence from the membrane-permeable dye in nonviable cells. Themasking agent also appeared to block fluorescence from themembrane-impermeable fluorescent dye in nonviable cells. Further themasking agent appeared to visually reduce a portion of fluorescenceassociated with the membrane-permeable fluorescent dye in the viablecells.

When the membrane-impermeable fluorescent quenching dye was combinedwith the membrane-permeable fluorescent dye, fluorescence from themembrane-permeable fluorescent dye disappeared from the nonviable cellsregardless of the order of dye addition. After sufficient time, thenonviable cells were only positive for the membrane-impermeablefluorescent quenching dye, with no visible fluorescence from themembrane-permeable fluorescent dye, which was confirmed by thefluorescence intensities quantification for both dyes present in thenonviable cells.

Example 2

In order to further examine the dyeing behavior and kinetics of themembrane-impermeable fluorescent quenching dye and themembrane-permeable fluorescent dye of Example 1 when mixed together, anadditional experiment was performed on day 7 of culture as follows.

On day 7, 20 μL of the membrane-permeable fluorescent dye was added at6× concentration to each well. The cells were incubated with dye at 37°C. for 1 hour. Confocal fluorescent microscopy was performed afterincubation. About 20 μL of the membrane-impermeable fluorescentquenching dye was added directly to the same well on the stage at 6×concentration without disturbing the cells.

Dynamic confocal fluorescent microscopy images were taken of the cellsimmediately after addition of the membrane-impermeable fluorescentquenching dye (FIG. 2A, 2B), as well as at 5 min (FIG. 2C, 2D), 20 min(FIG. 2E, 2F), 30 min (FIG. 2G, 2H) and 45 min (FIG. 2I, 2J) afteraddition.

The lower images (FIGS. B, D, F, H, & J) of each pair of images shows azoomed in view of the dyed cells in the upper images (FIGS. A, C, E, G,& I). In the portion of each of FIGS. B, D, F, H, & J indicated by thewhite boxes, cells that were originally dyed with the membrane-permeablefluorescent dye (green) begin to become red (positive for themembrane-impermeable fluorescent quenching dye), which is visuallynoticeable after 20-30 minutes. The brightest images in terms offluorescence intensity was acquired at 45 minutes after addition of thedye (FIG. 2I, 2J). Fluorescence intensity values demonstrated anincrease over time of the membrane-impermeable fluorescent quenching dyeintensity, accompanied by a corresponding significant decrease over timein the membrane-permeable fluorescent dye fluorescence.

By the 45 min, there was negligible membrane-permeable fluorescentdyeing of the nonviable cells and the nonviable cells were positive forthe membrane-impermeable fluorescent quenching dye.

Discussion

Without wishing to be bound by theory, the images of Example 2 areconsistent with displacement and/or quenching of the membrane-permeablefluorescent dye by the membrane-impermeable fluorescent quenching dyewithin the nonviable cells. These results are consistent with analysisof the experiment on day 4 (Example 1) in which the nonviable cells nolonger exhibited fluorescence associated with the membrane-permeablefluorescent dye. The result of these examples demonstrates selective,mutually exclusive fluorescent dyeing of the viable and nonviable cellsby the membrane-permeable fluorescent dye and the membrane-impermeablefluorescent quenching dye, respectively.

The disclosure of the present application includes several embodiments,which may share common properties and features. The properties andfeatures of one embodiment may be combined with properties and featuresof other embodiments. Similarly, a single property or feature orcombination of properties or features in any embodiment may constitute afurther embodiment.

Recitation of ranges of values herein are intended to illustrate eachseparate value falling within the range, and unless otherwise indicatedherein, each individual value is incorporated into the specification asif it were individually recited herein.

The term “about” refers to a range of values of plus or minus 20% of aspecified value. For example, the phrase “about 200” includes plus orminus 20% of 200, or from 160 to 240, unless specifically indicatedotherwise or contradicted by context.

Ranges may be expressed herein as from “about” or “approximately” oneparticular value to “about” or “approximately” another particular value.When such a range is expressed, another embodiment includes between eachsuch pair of particular values. Similarly, when values are expressed asapproximations, by use of the antecedent “about” or “approximate” itwill be understood that each particular value forms another embodiment.

It is understood that the endpoints of each of the ranges aresignificant both in relation to the other endpoint and independently ofthe other endpoint. It is also understood that there are a number ofvalues disclosed, wherein each value is also disclosed as “about” thatparticular value in addition to the value itself. For example, if thevalue “10” is disclosed, then “about 10” is also disclosed. It is alsounderstood that when a value is disclosed that is “less than or equal tothe value” or “greater than or equal to the value” possible rangesbetween these values are also disclosed, as appropriately understood bythe expert with ordinary skills in the art. For example, if the value“10” is disclosed the “less than or equal to 10” as well as “greaterthan or equal to 10” is also disclosed.

All methods described herein can be performed in any suitable orderunless otherwise indicated herein or otherwise clearly contradicted bycontext. Units, prefixes, and symbols are denoted in their SystèmeInternational de Unites (SI) accepted form unless otherwise specified.

The following terms, as used herein, have the meanings ascribed to themunless specified otherwise.

As used herein, the term “administering” means the introduction of acomposition into a container, well, cell, or tissue culture medium, or(as appropriate) onto cells, tissues or surfaces. Such methods arewell-known in the art. Any and all methods of introducing thecomposition are contemplated and the invention is not dependent on anyparticular means of introduction.

As used herein, the terms “agent” and “compound” are usedinterchangeably and mean any chemical compound, for example, amacromolecule or a small molecule disclosed herein. The agent may benaturally occurring (e.g. a herb or a natural product), non-naturallyoccurring, synthetic, purified, recombinant, and the like. An agent maybe used alone or in combination with other agents in the methodsdescribed herein.

As used herein, a “micro-tissue” means a small aggregation of biologicalcells, which may include any cells described herein, e.g., viable cells,nonviable cells, cancer cells, primary tumor cells, human cells, humanprimary tumor cells, and the like. In various embodiments the number ofcells in a micro-tissue is less than about one of: 1,000,000, 100,000,10,000, 1,000, 750, 500, 250, 200, 150, 125, 100, 75, 50, or 25, or arange between any two of the preceding values, for example, 25-1,000cells, 25-500 cells, 25-150 cells, and the like.

As used herein, “primary tissue” means tissue that was directly removedfrom an organism, for example by fine needle biopsy, core needle biopsy,or surgical biopsy, typically without further modification. “Primarytumor cells” are cells obtained from primary tissue in a particularsubject, by contrast with cancer cells from a cancer cell line.

As used herein, “live primary tissue” means primary tissue in which somecells are alive. As used herein, “cell suspension” and “tissuesuspension” may include cells, cell aggregates, tissue fragments, orother biological material suspended in an aqueous solution.

1. A method for selectively analyzing a sample for viable cells andnonviable cells, comprising: providing a sample comprising one or moreviable cells and/or one or more nonviable cells; contacting the samplewith a membrane-permeable fluorescent dye and a membrane-impermeablefluorescent quenching dye, the contacting effective to cause: the one ormore viable cells and/or the one or more nonviable cells to be dyed bythe membrane-permeable fluorescent dye, and the one or more nonviablecells to be dyed with the membrane-impermeable fluorescent quenchingdye, the membrane-permeable fluorescent dye characterized by a firstfluorescent excitation band and a first fluorescence emission band andthe membrane-impermeable fluorescent quenching dye characterized by asecond fluorescent excitation band and a second fluorescence emissionband; and illuminating the sample under conditions effective to cause:emitting of the first fluorescence emission band from the one or moreviable cells dyed by the membrane-permeable fluorescent dye, emitting ofthe second fluorescence emission band from the one or more nonviablecells dyed by the membrane-impermeable fluorescent quenching dye, andquenching of at least a portion of fluorescence of themembrane-permeable fluorescent dye in the one or more nonviable cells bythe membrane-impermeable fluorescent quenching dye; and selectivelyanalyzing the sample for: a presence of the one or more viable cellsaccording to the first fluorescence emission band and/or a presence ofthe one or more nonviable cells according to the second fluorescenceemission band.
 2. The method of claim 1, selectively analyzing thesample comprising detecting a number of the one or more viable cellspresent in the sample and a number of the one or more nonviable cellspresent in the sample.
 3. The method of claim 1, wherein: illuminatingthe sample comprises selectively illuminating in: the first excitationband corresponding to the membrane-permeable fluorescent dye and/or thesecond excitation band corresponding to the membrane-impermeablefluorescent quenching dye; and selectively analyzing the samplecomprises analyzing light emitted from the sample for the firstfluorescence emission band and the second fluorescence emission band;and further comprising distinguishing the one or more viable cellsand/or the one or more nonviable cells according to a spectraldifference between the first fluorescence emission band and the secondfluorescence emission band.
 4. The method of claim 1, selectivelyanalyzing the sample comprising: acquiring an image of the sample usinglight emitted by the first fluorescence emission band and the secondfluorescence emission band; and determining a number of the one or moreviable cells in the image according to light emitted by the firstfluorescence emission band, and a number of the one or more nonviablecells in the image according to light emitted by the second fluorescenceemission band.
 5. The method of claim 1, illuminating and selectivelyanalyzing the sample comprising using one or more of: fluorescenceimaging, fluorescence spectroscopy, fluorescence imaging microscopy,epifluorescence microscopy, confocal fluorescence imaging microscopy, afluorometer, a fluorescence microplate reader, and fluorescence flowcytometry.
 6. The method of claim 1, comprising providing the sample ina cell culture device, the cell culture device comprising at least oneof: a multiwell plate, a multiwell strip, an optical cell, and a flowcytometry apparatus.
 7. The method of claim 6, the cell culture devicecomprising at least one optically flat window, the selectively analyzingthe sample comprising conducting confocal fluorescence imagingmicroscopy of the sample through the at least one optically flat imagingwindow.
 8. The method of claim 1, further comprising culturing the oneor more viable cells in the sample under cell culture conditions.
 9. Themethod of claim 1, selectively analyzing the sample being conducted attwo or more points in time to determine a presence or an absence of achange in a number of the one or more viable cells and/or a number ofthe one or more nonviable cells.
 10. The method of claim 1, furthercomprising contacting the sample with at least one agent, selectivelyanalyzing the sample comprising analyzing the one or more viable cellsand/or the one or more nonviable cells for a presence or an absence of achange in response to the at least one agent.
 11. The method of claim10, wherein analyzing the presence or the absence of the response ischaracterized with respect to one or more of: an overall sampleconcentration, a concentration gradient in the sample, a time variationof the overall sample concentration, and a time variation of theconcentration gradient in the sample.
 12. The method of claim 10, the atleast one agent comprising an anticancer agent, a therapeutic drug usedas an adjunct in cancer therapy, and a compound suspected of modulatingcancer therapy.
 13. The method of claim 1, the sample comprising athree-dimensional micro-tissue formed of a plurality of the one or moreviable cells and/or the one or more nonviable cells.
 14. The method ofclaim 1, the sample comprising one of prokaryotic cells, eukaryoticcells, mammalian cells, human cells, cancer cells, primary tumor cells,primary tumor cells from a single human subject, or cells of apatient-derived cancer cell xenograft.
 15. The method of claim 1,comprising one of: contacting the sample with the membrane-permeablefluorescent dye before the membrane-impermeable fluorescent quenchingdye; contacting the sample with the membrane-permeable fluorescent dyeafter the membrane-impermeable fluorescent quenching dye; contacting thesample with the membrane-permeable fluorescent dye at the same time asthe membrane-impermeable fluorescent quenching dye; and contacting thesample with a composition comprising the membrane-permeable fluorescentdye together with the membrane-impermeable fluorescent quenching dye.16. The method of claim 1, the membrane-permeable fluorescent dye andthe membrane-impermeable fluorescent quenching dye being nucleic acidbinding dyes.
 17. The method of claim 1, the amount of themembrane-impermeable fluorescent quenching dye being effective tosubstantially quench fluorescence of the membrane-permeable fluorescentdye in the one or more nonviable cells.
 18. The method of claim 1, thefirst fluorescent emission band characterized by an overlap with anexcitation band of the membrane-impermeable fluorescent quenching dye,the overlap being effective to provide the quenching of at least aportion of fluorescence of the membrane-permeable fluorescent dye in theone or more nonviable cells by the membrane-impermeable fluorescentquenching dye.
 19. The method of claim 1, the membrane-permeablefluorescent dye being selected from Table I and the membrane-impermeablefluorescent quenching dye being selected from Table II.
 20. The methodof claim 1, the membrane-permeable fluorescent dye and themembrane-impermeable fluorescent quenching dye being a dye pair (a) or(b) selected from Table III.